Slocum Lake
Lake County, IllinoisView mapDirections
Illinois EPA publishes the water-quality measurements for Slocum Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Noxious aquatic plants
- 36 ft max depth
- Limited data
Slocum Lake in Lake County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Chlorophyll-a (algae): 90.3 µg/L.
Slocum Lake is a highly nutrient-loaded hypereutrophic lake in Lake County, Illinois with an estimated average depth of about 36 feet. Compared to the 18 other monitored lakes in Lake County, Slocum Lake ranks #19 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2021-08-10. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Slocum Lake is listed impaired under Clean Water Act §303(d) (IR 5) for noxious aquatic plants, nutrients (phosphorus, nitrogen), turbidity. Check local advisories before you swim.
Whether Slocum Lake is safe to swim in today is a call for the Illinois Environmental Protection Agency and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Slocum Lake
These are the measurements Illinois EPA publishes for Slocum Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Chlorophyll-a 90.3 µg/L. TSI 75.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | 90.3µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 75 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Slocum Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~36 ft est.
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Illinois has not published bathymetry for Slocum Lake.
Lake Size & Watershed
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Surface area
220 acres
HydroLAKES / HydroSHEDS
Shoreline
2.6 mi
HydroLAKES / HydroSHEDS
Elevation
738 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Stays via Stay22
Stays near Slocum Lake
Compare lakeside cabins, hotels, and vacation rentals near Slocum Lake in Lake County, Illinois — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Slocum Lake are listed below.
Top-rated places to stay near Slocum Lake
Prices for Nov 6–8, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Illinois’s top lakes →
Follow Slocum Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Slocum Lake
EPA Impairment Status
Slocum Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Other.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IL_RTP · Official waterbody report
Nearby Lakes in Lake County
Frequently asked questions about Slocum Lake
Where is Slocum Lake?
- Slocum Lake is a lake in Lake County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.
What is the water quality of Slocum Lake?
- Slocum Lake in Lake County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Chlorophyll-a (algae): 90.3 µg/L.
Is Slocum Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Slocum Lake is listed impaired under Clean Water Act §303(d) (IR 5) for noxious aquatic plants, nutrients (phosphorus, nitrogen), turbidity. Check local advisories before you swim.
How deep is Slocum Lake?
- No published bathymetric survey covers Slocum Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 36 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Slocum Lake across LakeQuality
8.4 mi away · cable-pulled, no boat wake
Species activity outlook by water temperature and season
Top lakes and where to stay in the Chain O'Lakes area
Where to stay at Illinois's top lakes, each with its readings
Illinois's cleanest lakes, ranked on agency measurements
More lakes in Illinois
Other Lakes in Illinois
Hypereutrophic Lakes in Illinois
Where this data comes from
6 measurements from 1 monitoring station, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- illinois epa
IL_EPA_WQX6 samples · 2021
Analytical methods
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)